Where exactly are the coins when I would put them in there? I assume on MGW addresses?
Yes. Coins are deposited on multisig addresses bound to the Nxt/SuperNET address that requested the deposit address. All coins sent to that address will trigger in the MGW servers an asset transfer with the corresponding amount of superCOIN.
Please remember that the deposit addresses are exactly that - a way to make deposits of other coins into the Nxt blockchain using assets, and that you should not search those addresses in the coin blockchain to check the coin balance in your Nxt account. Your balance is the number of assets you have, while the balance in MGW addresses will fluctuate due to internal redistribution of coins across multiple multisig accounts.
There is a question I have: Where is the blockchain that it uses?
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Where is the NRS located that I am communicating with? I have local copy running does it use that one?
SuperNET Lite does not use any local blockchain, it can be run standalone. It uses Jay Nxt public nodes (see
http://jnxt.org/)
Note that you can also access a Nxt Jay Wallet within SuperNET Lite. Click on the Menu button in the top right, and select "Advanced".
Another question is regarding the 'PIN' number- I couldn't find any explanation about that, waht about that?
Since the early releases of SuperNET Lite were aimed to be as accessible as possible for new users, the PIN login feature was introduced as a way to simplify both the login process and the authentication to send transactions to the network.
In the login page you can introduce your passphrase only once, and vinculate it to a short PIN. The passphrase is cached, and from then on (or at least for as long as you don't clean your browser's cache) you can select the imported account from the login drop down box, and just type the PIN to login. When submitting a transaction, the cached password will be used to sign the transaction locally and then broadcast it to the Nxt network. So same as with Jay or MyNxt wallet, the passphrase does not leave your computer.
However, the particular details of different login options in the next releases are still being discussed.